package com.watire.xiamivd.indicator;

import android.content.Context;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.os.Parcel;
import android.os.Parcelable;
import android.support.v4.view.MotionEventCompat;
import android.support.v4.view.ViewConfigurationCompat;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;

import com.watire.xiamivd.ExtendedViewPager;
import com.watire.xiamivd.R;

/**
 * Draws circles (one for each view). The current view position is filled and
 * others are only stroked.
 */
public class CirclePageIndicator extends View implements PageIndicator {

	public static final int HORIZONTAL = 0;
	public static final int VERTICAL = 1;

	private float mRadius;
	private final Paint mPaintStroke;
	private final Paint mPaintFill;
	private ExtendedViewPager mViewPager;
	private ExtendedViewPager.OnPageChangeListener mListener;
	private int mCurrentPage;
	private int mSnapPage;
	private int mCurrentOffset;
	private int mScrollState;
	private int mPageSize;
	private int mOrientation;
	private boolean mCentered;
	private boolean mSnap;

	private static final int INVALID_POINTER = -1;

	private int mTouchSlop;
	private float mLastMotionX = -1;
	private int mActivePointerId = INVALID_POINTER;
	private boolean mIsDragging;

	public CirclePageIndicator(Context context) {
		this(context, null);
	}

	public CirclePageIndicator(Context context, AttributeSet attrs) {
		this(context, attrs, R.attr.vpiCirclePageIndicatorStyle);
	}

	public CirclePageIndicator(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);

		// Load defaults from resources
		final Resources res = getResources();
		final int defaultFillColor = res.getColor(R.color.default_circle_indicator_fill_color);
		final int defaultOrientation = res.getInteger(R.integer.default_circle_indicator_orientation);
		final int defaultStrokeColor = res.getColor(R.color.default_circle_indicator_stroke_color);
		final float defaultStrokeWidth = res.getDimension(R.dimen.default_circle_indicator_stroke_width);
		final float defaultRadius = res.getDimension(R.dimen.default_circle_indicator_radius);
		final boolean defaultCentered = res.getBoolean(R.bool.default_circle_indicator_centered);
		final boolean defaultSnap = res.getBoolean(R.bool.default_circle_indicator_snap);

		// Retrieve styles attributes
		TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CirclePageIndicator, defStyle,
				R.style.Widget_CirclePageIndicator);

		mCentered = a.getBoolean(R.styleable.CirclePageIndicator_centered, defaultCentered);
		mOrientation = a.getInt(R.styleable.CirclePageIndicator_orientation, defaultOrientation);
		mPaintStroke = new Paint(Paint.ANTI_ALIAS_FLAG);
		mPaintStroke.setStyle(Paint.Style.STROKE);
		mPaintStroke.setColor(a.getColor(R.styleable.CirclePageIndicator_strokeColor, defaultStrokeColor));
		mPaintStroke.setStrokeWidth(a.getDimension(R.styleable.CirclePageIndicator_strokeWidth, defaultStrokeWidth));
		mPaintFill = new Paint(Paint.ANTI_ALIAS_FLAG);
		mPaintFill.setStyle(Paint.Style.FILL);
		mPaintFill.setColor(a.getColor(R.styleable.CirclePageIndicator_fillColor, defaultFillColor));
		mRadius = a.getDimension(R.styleable.CirclePageIndicator_radius, defaultRadius);
		mSnap = a.getBoolean(R.styleable.CirclePageIndicator_snap, defaultSnap);

		a.recycle();

		final ViewConfiguration configuration = ViewConfiguration.get(context);
		mTouchSlop = ViewConfigurationCompat.getScaledPagingTouchSlop(configuration);
	}

	public int getFillColor() {
		return mPaintFill.getColor();
	}

	public int getOrientation() {
		return mOrientation;
	}

	public float getRadius() {
		return mRadius;
	}

	public int getStrokeColor() {
		return mPaintStroke.getColor();
	}

	public float getStrokeWidth() {
		return mPaintStroke.getStrokeWidth();
	}

	public boolean isCentered() {
		return mCentered;
	}

	public boolean isSnap() {
		return mSnap;
	}

	@Override
	public void notifyDataSetChanged() {
		invalidate();
	}

	@Override
	public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
		mCurrentPage = position;
		mCurrentOffset = positionOffsetPixels;
		updatePageSize();
		invalidate();

		if (mListener != null) {
			mListener.onPageScrolled(position, positionOffset, positionOffsetPixels);
		}
	}

	@Override
	public void onPageScrollStateChanged(int state) {
		mScrollState = state;

		if (mListener != null) {
			mListener.onPageScrollStateChanged(state);
		}
	}

	@Override
	public void onPageSelected(int position) {
		if (mSnap || mScrollState == ExtendedViewPager.SCROLL_STATE_IDLE) {
			mCurrentPage = position;
			mSnapPage = position;
			invalidate();
		}

		if (mListener != null) {
			mListener.onPageSelected(position);
		}
	}

	@Override
	public void onRestoreInstanceState(Parcelable state) {
		SavedState savedState = (SavedState) state;
		super.onRestoreInstanceState(savedState.getSuperState());
		mCurrentPage = savedState.currentPage;
		mSnapPage = savedState.currentPage;
		requestLayout();
	}

	@Override
	public Parcelable onSaveInstanceState() {
		Parcelable superState = super.onSaveInstanceState();
		SavedState savedState = new SavedState(superState);
		savedState.currentPage = mCurrentPage;
		return savedState;
	}

	@Override
	public boolean onTouchEvent(android.view.MotionEvent ev) {
		if (mViewPager == null || mViewPager.getAdapter().getCount() == 0) return false;

		final int action = ev.getAction();

		switch (action & MotionEventCompat.ACTION_MASK) {
			case MotionEvent.ACTION_DOWN:
				mActivePointerId = MotionEventCompat.getPointerId(ev, 0);
				mLastMotionX = ev.getX();
				break;

			case MotionEvent.ACTION_MOVE: {
				final int activePointerIndex = MotionEventCompat.findPointerIndex(ev, mActivePointerId);
				final float x = MotionEventCompat.getX(ev, activePointerIndex);
				final float deltaX = x - mLastMotionX;

				if (!mIsDragging) {
					if (Math.abs(deltaX) > mTouchSlop) {
						mIsDragging = true;
					}
				}

				if (mIsDragging) {
					if (!mViewPager.isFakeDragging()) {
						mViewPager.beginFakeDrag();
					}

					mLastMotionX = x;

					mViewPager.fakeDragBy(deltaX);
				}

				break;
			}

			case MotionEvent.ACTION_CANCEL:
			case MotionEvent.ACTION_UP:
				if (!mIsDragging) {
					final int count = mViewPager.getAdapter().getCount();
					final int width = getWidth();
					final float halfWidth = width / 2f;
					final float sixthWidth = width / 6f;

					if (mCurrentPage > 0 && ev.getX() < halfWidth - sixthWidth) {
						mViewPager.setCurrentItem(mCurrentPage - 1);
						return true;
					} else if (mCurrentPage < count - 1 && ev.getX() > halfWidth + sixthWidth) {
						mViewPager.setCurrentItem(mCurrentPage + 1);
						return true;
					}
				}

				mIsDragging = false;
				mActivePointerId = INVALID_POINTER;
				if (mViewPager.isFakeDragging()) {
					mViewPager.endFakeDrag();
				}
				break;

			case MotionEventCompat.ACTION_POINTER_DOWN: {
				final int index = MotionEventCompat.getActionIndex(ev);
				final float x = MotionEventCompat.getX(ev, index);
				mLastMotionX = x;
				mActivePointerId = MotionEventCompat.getPointerId(ev, index);
				break;
			}

			case MotionEventCompat.ACTION_POINTER_UP:
				final int pointerIndex = MotionEventCompat.getActionIndex(ev);
				final int pointerId = MotionEventCompat.getPointerId(ev, pointerIndex);
				if (pointerId == mActivePointerId) {
					final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
					mActivePointerId = MotionEventCompat.getPointerId(ev, newPointerIndex);
				}
				mLastMotionX = MotionEventCompat.getX(ev, MotionEventCompat.findPointerIndex(ev, mActivePointerId));
				break;
		}

		return true;
	}

	public void setCentered(boolean centered) {
		mCentered = centered;
		invalidate();
	};

	@Override
	public void setCurrentItem(int item) {
		if (mViewPager == null) throw new IllegalStateException("ViewPager has not been bound.");
		mViewPager.setCurrentItem(item);
		mCurrentPage = item;
		invalidate();
	}

	public void setFillColor(int fillColor) {
		mPaintFill.setColor(fillColor);
		invalidate();
	}

	@Override
	public void setOnPageChangeListener(ExtendedViewPager.OnPageChangeListener listener) {
		mListener = listener;
	}

	public void setOrientation(int orientation) {
		switch (orientation) {
			case HORIZONTAL:
			case VERTICAL:
				mOrientation = orientation;
				updatePageSize();
				requestLayout();
				break;

			default:
				throw new IllegalArgumentException("Orientation must be either HORIZONTAL or VERTICAL.");
		}
	}

	@Override
	public void setPagingEnabled(boolean enabled) {
		mViewPager.setPagingEnabled(enabled);
	}

	public void setRadius(float radius) {
		mRadius = radius;
		invalidate();
	}

	public void setSnap(boolean snap) {
		mSnap = snap;
		invalidate();
	}

	public void setStrokeColor(int strokeColor) {
		mPaintStroke.setColor(strokeColor);
		invalidate();
	}

	public void setStrokeWidth(float strokeWidth) {
		mPaintStroke.setStrokeWidth(strokeWidth);
		invalidate();
	}

	@Override
	public void setViewPager(ExtendedViewPager pager) {
		if (pager.getAdapter() == null) throw new IllegalStateException("ViewPager does not have adapter instance.");
		mViewPager = pager;
		mViewPager.setOnPageChangeListener(this);
		updatePageSize();
		invalidate();
	}

	@Override
	public void setViewPager(ExtendedViewPager pager, int initialPosition) {
		setViewPager(pager);
		setCurrentItem(initialPosition);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see android.view.View#onDraw(android.graphics.Canvas)
	 */
	@Override
	protected void onDraw(Canvas canvas) {
		super.onDraw(canvas);

		if (mViewPager == null) return;
		final int count = mViewPager.getAdapter().getCount();
		if (count == 0) return;

		int longSize;
		int longPaddingBefore;
		int longPaddingAfter;
		int shortPaddingBefore;
		if (mOrientation == HORIZONTAL) {
			longSize = getWidth();
			longPaddingBefore = getPaddingLeft();
			longPaddingAfter = getPaddingRight();
			shortPaddingBefore = getPaddingTop();
		} else {
			longSize = getHeight();
			longPaddingBefore = getPaddingTop();
			longPaddingAfter = getPaddingBottom();
			shortPaddingBefore = getPaddingLeft();
		}

		final float threeRadius = mRadius * 3;
		final float shortOffset = shortPaddingBefore + mRadius;
		float longOffset = longPaddingBefore + mRadius;
		if (mCentered) {
			longOffset += (longSize - longPaddingBefore - longPaddingAfter) / 2.0f - count * threeRadius / 2.0f;
		}

		float dX;
		float dY;

		// Draw stroked circles
		for (int iLoop = 0; iLoop < count; iLoop++) {
			float drawLong = longOffset + iLoop * threeRadius;
			if (mOrientation == HORIZONTAL) {
				dX = drawLong;
				dY = shortOffset;
			} else {
				dX = shortOffset;
				dY = drawLong;
			}
			canvas.drawCircle(dX, dY, mRadius, mPaintStroke);
		}

		// Draw the filled circle according to the current scroll
		float cx = (mSnap ? mSnapPage : mCurrentPage) * threeRadius;
		if (!mSnap && mPageSize != 0) {
			cx += mCurrentOffset * 1.0f / mPageSize * threeRadius;
		}
		if (mOrientation == HORIZONTAL) {
			dX = longOffset + cx;
			dY = shortOffset;
		} else {
			dX = shortOffset;
			dY = longOffset + cx;
		}
		canvas.drawCircle(dX, dY, mRadius, mPaintFill);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see android.view.View#onMeasure(int, int)
	 */
	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		if (mOrientation == HORIZONTAL) {
			setMeasuredDimension(measureLong(widthMeasureSpec), measureShort(heightMeasureSpec));
		} else {
			setMeasuredDimension(measureShort(widthMeasureSpec), measureLong(heightMeasureSpec));
		}
	}

	/**
	 * Determines the width of this view
	 * 
	 * @param measureSpec A measureSpec packed into an int
	 * @return The width of the view, honoring constraints from measureSpec
	 */
	private int measureLong(int measureSpec) {
		int result = 0;
		int specMode = MeasureSpec.getMode(measureSpec);
		int specSize = MeasureSpec.getSize(measureSpec);

		if (specMode == MeasureSpec.EXACTLY || mViewPager == null) {
			// We were told how big to be
			result = specSize;
		} else {
			// Calculate the width according the views count
			final int count = mViewPager.getAdapter().getCount();
			result = (int) (getPaddingLeft() + getPaddingRight() + count * 2 * mRadius + (count - 1) * mRadius + 1);
			// Respect AT_MOST value if that was what is called for by
			// measureSpec
			if (specMode == MeasureSpec.AT_MOST) {
				result = Math.min(result, specSize);
			}
		}
		return result;
	}

	/**
	 * Determines the height of this view
	 * 
	 * @param measureSpec A measureSpec packed into an int
	 * @return The height of the view, honoring constraints from measureSpec
	 */
	private int measureShort(int measureSpec) {
		int result = 0;
		int specMode = MeasureSpec.getMode(measureSpec);
		int specSize = MeasureSpec.getSize(measureSpec);

		if (specMode == MeasureSpec.EXACTLY) {
			// We were told how big to be
			result = specSize;
		} else {
			// Measure the height
			result = (int) (2 * mRadius + getPaddingTop() + getPaddingBottom() + 1);
			// Respect AT_MOST value if that was what is called for by
			// measureSpec
			if (specMode == MeasureSpec.AT_MOST) {
				result = Math.min(result, specSize);
			}
		}
		return result;
	}

	private void updatePageSize() {
		if (mViewPager != null) {
			mPageSize = mOrientation == HORIZONTAL ? mViewPager.getWidth() : mViewPager.getHeight();
		}
	}

	static class SavedState extends BaseSavedState {

		int currentPage;

		public SavedState(Parcelable superState) {
			super(superState);
		}

		private SavedState(Parcel in) {
			super(in);
			currentPage = in.readInt();
		}

		@Override
		public void writeToParcel(Parcel dest, int flags) {
			super.writeToParcel(dest, flags);
			dest.writeInt(currentPage);
		}

		public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() {

			@Override
			public SavedState createFromParcel(Parcel in) {
				return new SavedState(in);
			}

			@Override
			public SavedState[] newArray(int size) {
				return new SavedState[size];
			}
		};
	}
}